A security perimeter refers to a physical aspect of the system that prevents attackers from accessing confidential information or manipulating data to break intended functionality. A security perimeter can be designed in the hardware, software or using a combination of both. The strength of a security perimeter is measured by its ability to prevent the many known attack scenarios. A proper implementation of a security perimeter should be built upon a trusted framework. Some examples of a trusted framework include secure boot, trusted processor module, etc.
Trusted code is software that can only be executed on a trusted processor module or trusted platform module (TPM). The trusted code protection format generally has encryption and/or integrity built in.
Existing techniques rely on implementing a localized security perimeter on the device. The strength of this security perimeter is dependent on the available resources on the device, which translates to higher cost.